Although neuropeptides are contained within primary afferent fibers located in dental pulp, the pharmacological regulation of their release has been incompletely characterized. This area of research has been limited by access, since dental pulp is encased in a hard structure similar to the encasement of the spinal cord within the vertebral column. However, recent studies have been successfully carried out with in vitro superfusion of spinal cord preparations. These studies have determined, to a large extent, the pharmacological regulation of neuropeptide release from spinal cord tissue. Similarly, this proposal will employ an in vitro superfusion of dental pulp to accomplish the following specific aims: 1) Compare capsaicin to potassium for evoking release of immunoreactive substance P (iSP) and calcitonin gene-related peptide (iCGRP) from dental pulp using an in vitro superfusion preparation. 2) Characterize the physiologic mechanisms mediating pulpal secretion of neuropeptides. 3) Determine whether bradykinin and prostaglandin E2 (PGE2) are effective for evoking the release of iSP and iCGRP from dental pulp. 4) Determine whether adrenergic agonists selective for the alpha and beta receptor subtypes are effective in modulating basal or evoked-release of iSP and iCGRP from dental pulp superfusates. Our initial data demonstrates the feasibility of this approach. Administration of a potassium pulse to a superfused dental pulp preparation elicits a near six-fold increase in iSP and a near two-fold increase in iCGRP as compared to basal levels of release. This method appears suitable for more comprehensive studies determining the pharmacological regulation of neuropeptide release from dental pulp. Development of an in vitro model to evaluate these regulatory mechanisms may prove useful in studies on the physiology of primary afferent fibers mediating neurogenic inflammation and may serve to identify potentially useful therapeutic interventions.